// GtkSharp.Generation.StructBase.cs - The Structure/Boxed Base Class.
//
// Authors:
//   Mike Kestner <mkestner@speakeasy.net>
//   Stephan Sundermann <stephansundermann@gmail.com>
//
// Copyright (c) 2001-2003 Mike Kestner
// Copyright (c) 2013 Stephan Sundermann
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the GNU General Public
// License as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public
// License along with this program; if not, write to the
// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.


namespace GtkSharp.Generation {

	using System;
	using System.Collections.Generic;
	using System.IO;
	using System.Text;
	using System.Text.RegularExpressions;
	using System.Xml;

	public abstract class StructBase : ClassBase, IManualMarshaler {

		IList<StructField> fields = new List<StructField>();
		bool need_read_native = false;

		protected StructBase(XmlElement ns, XmlElement elem) : base(ns, elem) {
			foreach (XmlNode node in elem.ChildNodes) {

				if (!(node is XmlElement)) continue;
				XmlElement member = (XmlElement)node;

				switch (node.Name) {
					case "field":
						fields.Add(new StructField(member, this));
						break;

					case "callback":
						Statistics.IgnoreCount++;
						break;

					default:
						if (!IsNodeNameHandled(node.Name))
							Console.WriteLine("Unexpected node " + node.Name + " in " + CName);
						break;
				}
			}
		}

		public override string DefaultValue {
			get {
				return QualifiedName + ".Zero";
			}
		}

		public override string MarshalType {
			get {
				return "IntPtr";
			}
		}

		public override string AssignToName {
			get { throw new NotImplementedException(); }
		}

		public override string CallByName() {
			return "this_as_native";
		}

		public override string CallByName(string var) {
			return var + "_as_native";
		}

		public override string FromNative(string var) {
			if (DisableNew)
				return var + " == IntPtr.Zero ? " + QualifiedName + ".Zero : (" + QualifiedName + ") System.Runtime.InteropServices.Marshal.PtrToStructure (" + var + ", typeof (" + QualifiedName + "))";
			else
				return QualifiedName + ".New (" + var + ")";
		}

		public string AllocNative(string var) {
			return "GLib.Marshaller.StructureToPtrAlloc (" + var + ")";
		}

		public string ReleaseNative(string var) {
			return "Marshal.FreeHGlobal (" + var + ")";
		}

		private bool DisableNew {
			get {
				return Elem.GetAttributeAsBoolean("disable_new");
			}
		}

		public virtual bool Union {
			get {
				return false;
			}
		}

		protected void GenEqualsAndHash(StreamWriter sw) {
			int bitfields = 0;
			bool need_field = true;
			StringBuilder hashcode = new StringBuilder();
			StringBuilder equals = new StringBuilder();

			hashcode.Append("this.GetType ().FullName.GetHashCode ()");
			equals.Append("true");

			foreach (StructField field in fields) {
				if (field.IsPadding || field.Hidden)
					continue;
				if (field.IsBitfield) {
					if (need_field) {
						equals.Append(" && _bitfield");
						equals.Append(bitfields);
						equals.Append(".Equals (other._bitfield");
						equals.Append(bitfields);
						equals.Append(")");
						hashcode.Append(" ^ ");
						hashcode.Append("_bitfield");
						hashcode.Append(bitfields++);
						hashcode.Append(".GetHashCode ()");
						need_field = false;
					}
				} else {
					need_field = true;
					equals.Append(" && ");
					equals.Append(field.EqualityName);
					equals.Append(".Equals (other.");
					equals.Append(field.EqualityName);
					equals.Append(")");
					hashcode.Append(" ^ ");
					hashcode.Append(field.EqualityName);
					hashcode.Append(".GetHashCode ()");
				}
			}

			bool genEquals = !Elem.GetAttributeAsBoolean("noequals");
			if (genEquals && Methods.ContainsKey("Equals")) {
				var equalsMethod = Methods["Equals"];
				if (equalsMethod.Parameters.Count == 1 && equalsMethod.Parameters[0].CSType == QualifiedName) {
					genEquals = false;
				}
			}

			if (genEquals) {
				sw.WriteLine("\t\tpublic bool Equals ({0} other)", Name);
				sw.WriteLine("\t\t{");
				sw.WriteLine("\t\t\treturn {0};", equals.ToString());
				sw.WriteLine("\t\t}");
				sw.WriteLine();
			}
			sw.WriteLine("\t\tpublic override bool Equals (object other)");
			sw.WriteLine("\t\t{");
			sw.WriteLine("\t\t\treturn other is {0} && Equals (({0}) other);", Name);
			sw.WriteLine("\t\t}");
			sw.WriteLine();
			if (Elem.GetAttributeAsBoolean("nohash"))
				return;
			sw.WriteLine("\t\tpublic override int GetHashCode ()");
			sw.WriteLine("\t\t{");
			sw.WriteLine("\t\t\treturn {0};", hashcode.ToString());
			sw.WriteLine("\t\t}");
			sw.WriteLine();

		}

		protected new void GenFields(GenerationInfo gen_info) {
			int bitfields = 0;
			bool need_field = true;
			StreamWriter sw = gen_info.Writer;

			foreach (StructField field in fields) {
				if (Union)
					sw.WriteLine("\t\t[FieldOffset(0)]");
				if (field.IsBitfield) {
					if (need_field) {
						sw.WriteLine("\t\tprivate uint _bitfield{0};\n", bitfields++);
						need_field = false;
					}
				} else
					need_field = true;
				field.Generate(gen_info, "\t\t");
			}
		}

		public override bool Validate() {
			LogWriter log = new LogWriter(QualifiedName);
			foreach (StructField field in fields) {
				if (!field.Validate(log)) {
					if (!field.IsPointer)
						return false;
				}
			}

			return base.Validate();
		}

		public override bool CanGenerateABIStruct(LogWriter log) {
			log.Info("Not generating any ABI structs for managed structures");

			return false;
		}

		public override void Generate(GenerationInfo gen_info) {
			bool need_close = false;

			if (gen_info.Writer == null) {
				gen_info.Writer = gen_info.OpenStream(Name, NS);
				need_close = true;
			}

			StreamWriter sw = gen_info.Writer;

			sw.WriteLine("namespace " + NS + " {");
			sw.WriteLine();
			sw.WriteLine("\tusing System;");
			sw.WriteLine("\tusing System.Collections;");
			sw.WriteLine("\tusing System.Collections.Generic;");
			sw.WriteLine("\tusing System.Runtime.InteropServices;");
			sw.WriteLine();

			sw.WriteLine("#region Autogenerated code");
			if (IsDeprecated)
				sw.WriteLine("\t[Obsolete]");
			if (Union)
				sw.WriteLine("\t[StructLayout(LayoutKind.Explicit)]");
			else
				sw.WriteLine("\t[StructLayout(LayoutKind.Sequential)]");
			string access = IsInternal ? "internal" : "public";
			sw.WriteLine("\t" + access + " partial struct {0} : IEquatable<{0}> {{", Name);
			sw.WriteLine();

			need_read_native = false;
			GenFields(gen_info);
			sw.WriteLine();
			GenCtors(gen_info);
			GenMethods(gen_info, null, this);
			if (need_read_native)
				GenReadNative(sw);
			GenEqualsAndHash(sw);

			if (!need_close)
				return;

			sw.WriteLine("#endregion");

			sw.WriteLine("\t}");
			sw.WriteLine("}");
			sw.Close();
			gen_info.Writer = null;
		}

		protected override void GenCtors(GenerationInfo gen_info) {
			StreamWriter sw = gen_info.Writer;

			sw.WriteLine("\t\tpublic static {0} Zero = new {0} ();", QualifiedName);
			sw.WriteLine();
			if (!DisableNew) {
				sw.WriteLine("\t\tpublic static " + QualifiedName + " New(IntPtr raw) {");
				sw.WriteLine("\t\t\tif (raw == IntPtr.Zero)");
				sw.WriteLine("\t\t\t\treturn {0}.Zero;", QualifiedName);
				sw.WriteLine("\t\t\treturn ({0}) Marshal.PtrToStructure (raw, typeof ({0}));", QualifiedName);
				sw.WriteLine("\t\t}");
				sw.WriteLine();
			}

			foreach (Ctor ctor in Ctors)
				ctor.IsStatic = true;

			base.GenCtors(gen_info);
		}

		void GenReadNative(StreamWriter sw) {
			sw.WriteLine("\t\tstatic void ReadNative (IntPtr native, ref {0} target)", QualifiedName);
			sw.WriteLine("\t\t{");
			sw.WriteLine("\t\t\ttarget = New (native);");
			sw.WriteLine("\t\t}");
			sw.WriteLine();
		}

		public override void Prepare(StreamWriter sw, string indent) {
			sw.WriteLine(indent + "IntPtr this_as_native = System.Runtime.InteropServices.Marshal.AllocHGlobal (System.Runtime.InteropServices.Marshal.SizeOf (this));");
			sw.WriteLine(indent + "System.Runtime.InteropServices.Marshal.StructureToPtr (this, this_as_native, false);");
		}

		public override void Finish(StreamWriter sw, string indent) {
			need_read_native = true;
			sw.WriteLine(indent + "ReadNative (this_as_native, ref this);");
			sw.WriteLine(indent + "System.Runtime.InteropServices.Marshal.FreeHGlobal (this_as_native);");
		}
	}
}